First, make sure that as part of a follow-up call, a General Partner is participating. Without a GP participating, the opportunity is actually not advancing in a meaningful way.

Second, highlight what's new since last you spoke. It's likely that they identified some potential promise in what you're doing and want to check-in. The best way to build credibility is to show that the things you said you were going to do, you've done, and that momentum is building.

Third, answer their questions concisely and to the point, and no more than the answer to the question.

That's all the generalizable advice I can offer without knowing more of the specifics of your situation and what kind of investor you're dealing with. Happy to talk to you in a confidential call.